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Why Loudness Measurement Matters

More and more post-production is happening in-house in production companies, across Ireland and elsewhere. Central to this is cost-savings but if you’re going to do it, you need to do it correctly. Audio is one of the elements that is easy to make a mistake especially in terms of LUFS and delivering broadcast compressed audio sound to your programme delivery. Why does it matter?

Audio content requires specific loudness standards to sound clear and balanced across platforms. Loudness is measured in Loudness Units Full Scale (LUFS), a measure designed to match how humans perceive loudness. While decibels measure sound intensity, LUFS accounts for our sensitivity to different frequencies which is why it’s a more accurate way to ensure the perceived volume aligns with standards for streaming and broadcast.

Tools to Measure Loudness

1. Adobe Premiere Pro’s Loudness Meter

Premiere Pro’s built-in loudness meter provides a great tool for measuring audio levels but requires manual adjustment to achieve correct levels.

  • How to Access It: Open the Audio Track Mixer in the Essential Sound workspace, then add the loudness meter effect to the master track.
  • Metrics Displayed:
    • Integrated Loudness: Measures the entire track’s loudness from start to finish.
    • True Peak: Shows the maximum peak level to help prevent distortion.
    • Short-Term Loudness: A moving average over three seconds that highlights short-term loudness changes.
    • Momentary Loudness: A quick measurement of loudness changes over 400 milliseconds, useful for spotting sudden spikes.

While this meter provides readings, it won’t automatically adjust your audio. To meet a target (e.g., -14 LUFS for YouTube or an EBU R128 such as for RTÉ or TG4), you’ll need to adjust the levels manually in your mix.

2. WLM Plus Loudness Meter from Waves Audio

The WLM Plus Loudness Meter by Waves is a plugin that not only measures loudness but also includes a true peak limiter to keep your audio within specified loudness ranges, making it easier to meet platform requirements.

  • How to Use It: Add the WLM Plus plugin to the master track in Premiere Pro.
  • Key Features:
    • Presets for Various Standards: Choose from presets for YouTube, Spotify, Netflix, Apple Podcasts, and others, making it easy to align with platform-specific loudness targets.
    • True Peak Limiter: This feature automatically reduces gain to prevent audio from exceeding the target peak, saving you from having to manually adjust levels repeatedly.
    • Three Analysis Methods:
      • EBU Mode: Measures foreground audio as the loudness anchor, as used in broadcast.
      • LM1 Mode: Averages loudness across the full program, best for music-heavy content.
      • Dial Mode: Measures loudness based on dialogue detection, ideal for dialogue-centered content like podcasts.
    • Data Exporting: You can export readings in a spreadsheet, allowing you to document and verify your audio’s loudness for clients or standards compliance.

Step-by-Step Guide to Adjusting Loudness

  1. Set Your Target Loudness: Choose your target based on your platform (e.g., -14 LUFS for YouTube, -23 LUFS for broadcasters)
  2. Load the Loudness Meter: In Premiere Pro, use the built-in loudness meter or add the WLM Plus plugin for more detailed control.
  3. Check Your Metrics:
    • Play your audio and monitor the integrated loudness and true peak values to ensure they’re within the acceptable range.
    • For the built-in meter, note if adjustments are needed. With WLM Plus, engage the True Peak Limiter to automatically adjust peaks.
  4. Fine-Tune Levels: Adjust your mix levels or apply gain adjustments to reach your target loudness.
  5. Verify Your Results: Recheck the loudness metrics and, if using WLM Plus, confirm your adjustments meet the set target values.

Final Tips

  • Preset Convenience: The WLM Plus plugin’s presets allow you to meet specific loudness standards instantly, without manually setting targets for each platform.
  • Document Your Loudness: Export readings if needed to verify your audio complies with required standards, helpful for broadcast and corporate projects.
  • Take Control of Your Mix: By meeting platform loudness standards yourself, you prevent automatic adjustments by streaming services that can negatively impact your audio quality.

By using Premiere Pro’s built-in tools or the WLM Plus Loudness Meter from Waves, you’ll be well-equipped to ensure your audio meets the professional standards required across different media platforms. If only all DIY was this easy 🙂

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